This was an issue for me as well when I first began considering the Catholic faith. You see, we are heavily taught in Protestant faiths that any adult believer (who believes Jesus Christ to be the son of God, his life, death, and resurrection) is encouraged to receive communion. Church membership is not a barrier, nor should it ever be considered one.
So you see, it’s a whole new concept and one that ‘appears’ contary to Biblical teachings. It can be a VERY sore point for non-Catholics. It makes it seem like Catholics think that: 1) you’re an outsider - not good enough to partake; 2) church membership is what gets you into heaven; and 3) you’re not even considered a brother or sister in the Lord, even though you are devoted our Lord and Savior.
Once I got into RICA I understood that none of that is true. I think the barrier that creates the problem is that unless you understand and accept that this is the literal body and blood of our Lord Jesus Christ, it will remain an issue and problem. Catholics forget that most Protestants don’t know that we believe communion is the literal body and blood. In the Protestant faith, the bread and wine only *represent *our Lord. They can’t even grasp how we could think otherwise.
So, until you can help them to understand and accept this truth, they can’t understand how precious communion is to Catholics. So precious in fact, that you we require anyone who wishes to partake, to be in full and complete unity and accord with (not just our Church’s doctrine), but also with our fellow Catholic believers - since we partake as a community, in the unity, of this truth.
But further, as a community of believers who have studied, lived the lifestyle of what it means, and then finally, being granted this most precious privilege in a ceremony of joy and encouragement for all. In other words, we’re not withholding it from non-Catholics, rather it’s such a high privilege, that we require one to fully know, study, and understand what it all means - before being able to partake.
That’s no different than how, as a Protestant, you would object to someone partaking that didn’t have any concept of Jesus being the Son of God or what His death meant. You don’t look down on them or want them just not to have it; rather, you just desire them not to partake until they fully understand what they are partaking of because there’s more to it than just have bread and wine (or in most churches - grape juice). If you don’t understand, it’s just a lite snack! But more, that disrespects it’s meaning and something that is precious to your faith. So it is such, in the same way, to the Catholic Church.
If she really believed it all, she’d be a member. Obviously there’s reservations.